Centrifugal machine for separating and clarifying liquids



Oct. 1, 1 5 J. M. MAY E UX 2,808,201

CENTRIFUGAL MACHINE FOR SEPARATING AND CLARIFYING LIQUIDS Filed July 14,1954 2 Sheets-Sheet 1 \NVENTOR 0 SAN MAURICE MAYEUX ATTO R N EYSCENTRIFUGAL MACHINE FOR SEPARATING AND CLARIFYING LIQUIDS Jean MauriceMayeux, Algiers, Algeria Application July 14, 1954, Serial No. 443,401Claims priority, application France September 25, 1953 11 Claims. (Cl.233-28) nated, whether solid or liquid, before they may rest on a rigidsurface.

Those partitions, commonly called discs or dishes are conical in shape.

To justify the generalized use of this sort of partition, constructorsuse, as a base, measurements of the falling speed of solid particles, instatic decantation, wherein the time of decantation is effectively adirect function of the length of the paths followed by the productswhich are being decanted before they reach the bottom of the'vats.

The fact that, for a given liquid and a bowl having a given volume, theresults of the centrifugal clarification or of the centrifugalseparation of two or more liquids, are improved when the number of discsis increased was formerly thought to confirm validity of the analogywhich was believed'to exist between the static and the centrifugaldecantation. An improvement of the results, consequently, was sought inincreasing the volume and speed of the bowls, on the one hand, and, onthe other hand, in

decreasing the interval provided between the discs down to the limitindustrially imposed by the mechanical strength of the materials and thedimensions of the particles to be eliminated.

Applicant considers, on the contrary, that this decrease in the lengthsof the paths offers no interest in the case of dynamic decantationconstituted by centrifugal operations, and that there should besubstituted for this principle of a decrease of the paths that of thedecrease of the possible variations between the average speeds ofcirculationtowards the axis or towards the outsideof the'liquids andsolids introduced in the bowl, theoretically determined by theconstruction constants of the rotor and the extreme speeds ofcirculation towards the axis or outwards, caused, both in the radialdirection and in the axial direction by the vortices of the liquids.Applicant believes that, if, at the point where the centrifugal force ismaximum for a given liquid, the particles to be eliminated (whether theybe solid or liquid) have not been able to reach, under the action ofthis centrifugal force, a speed higher than that of the liquid stream inthe opposite direction, the length of the path is unimportant as well asthe time spent in the bowl.

.Certain anomalies in the results obtained from centrifugal operationsas compared with the results obtained by centrifugal operations in thelaboratory or by mere decantation, led the applicant to assume that therotors of centrifugal machines might, leaving aside the classicalprinciples of the present construction, be considerably im- 5 2,808,201Patented Oct. 1, 1957 proved both as concerns the effective hourlyoutput and the minimum size of particles of all natures capable of beingeliminated by centrifugal operations.

The invention resides in a centrifugal machine which, instead ofcomprising conical dishes like most of the existing machines, isprovided withperfectly plane partitions perpendicular to the axis of thebowl, as thin as possible and separated by distance-pieces the thicknessof which varies according to the materials to be treated and thedimensions of which are as small as possible so as to suppress allmeridian partitioning inside the stack of discs by placing theseinevitable distance-pieces outside the paths followed by the liquids andsolids towards the axis or towards the outside of the rotor.

The machine built according to the invention comprises a bowl', providedinside with a dividing partitioning, consisting of plane discs arrangedperpendicularly and concentrically with respect to the axis of the shaftdriving said 'bowl in a high speed rotation motion, said discs beingseparated from one another by spacing washers the thickness of which hasbeen selected according to the size and nature of the particles insuspension in the liquids to be treated in the machine.

The various features of the invention will appear from the followingdescription when read with referenceto the appended drawing wherein:

Fig. 1 is a vertical sectional view of the centrifugal machine alongitsaxis of rotation; i

Fig. 2 shows, in plane view, oneof the dividing discs on which areplaced spacing washers; i l i Fig. 3 shows the discin section alongtheline III- 1H ofFig.2; L,

Fig. 4 shows,sche'rnatically, the shortened path for the. liquids; p I

Fig. 5 shows, schematically, the outside path.

This description is that of a form of embodiment of the machine which isan object of the invention, this form of embodiment being mentioned onlyby way of amere example. p i

The rnachinecomprises a bowl 1 (Fig. 1) comprising a hub 2 for mountingit on a shaft 3 driven in a high speed rotation motion by any knownmeans. The hub 2 may bekeyed or not onto the shaft 3.

At the center of the bowl, a distributor 4 is arranged, the base 4a ofwhich is provided with radial channels 5 opening, at their lower endunder holes 5a located at a distance from the axis of the bowl equal tothat of the theoretical position of the surface of separation betweentwo liquids, selected for the considered bowl.

The base of the distributor supports a stack of dividing discs 6, planein shape, obtained by cutting out from metal blanks and, each one ofthem comprising two series of holes 6a (Fig. 2) and a series ofperipheral notches 6b.

The stack of discs is obtained by securing, on a lower flange 7,.pins 8for engagement with the holes 6a-of the, discs. The discs 6 can then bepassed on the pins 8 while separating them from one another by means ofspacing washers 9 also passed over the pins. e r

The flange 7 is provided with aperturesi'a coinciding with the notches6b of the discs 6-andtheapertures 5a of the channels 5 of thedistributorl. a 1

The washers 9 might be welded on the discs, but it is preferable toleave them independentofthe latterjso that it may be possible, byvarying their thickness, with 3 the same discs, to constitute stackgjnwhich the discs are spaced from one another accordingto the materials tobe treated. a

The discs are heldassembled in the shape of a stackby means of anupper'flange 10, on whichthe pins 8 arel held, by means ofnuts, forinstance. 7, .t

The number of discs depends, obviously, on the dimensions of the bowl 1and on their spacing, determined, as just set forth, according to thematerials to be treated.

The pins 8 are flush with the outer plane of each one of the flanges 7and 10 and the stack thus constituted is machined to remove any smalldiflerences which may occur in the discs. 7 V

The stack of discs 6 thus forms an assembly which it is not necessary todismantle when cleaning the machine, and which is interchangeable withother stacks having various characteristics. 7

The stack of discs 6 is covered with a cap 11 fitting on the bowl 1,with an interposed seal 12, under the pressure of a clamping ring 13screwed on the bowl 1.

In the cap 11 are fastened spouts 14 arranged radially and inclinedsubstantially at 45 The spouts fit into notches provided in the upperflange 10 which comprises further slots 10a for the passage of the lightliquid in the case of the separation of two liquids or of the singleclarified liquid in the case of the treatment of a single liquid. Theslots 10a face holes 16 provided in the cap 11. t

'On the cap 11 is screwed a ring 17 carrying a diaphragm 18 which makesit possible, in cooperation with the spouts 14 and by a suitable choiceof said elements, to adjust the working conditions for the bowl.

A neck or collar 19 associated with the cap 11 ensures the upward motionof the lighter liquid (case of the separation of two or more liquids) orof the single liquid, to the level necessary for its evacuation. Thedistance from the axis of the bowl to the outlet for the liquid may beadjusted by mounting on the neck a ring which acts as a throttle.

The machine is completed by flanges 20, 21, and 22 made of elasticmaterials selected according to the liquids to be treated and carried bythe receivers 23, 2.4 and 25 respectively. The flanges are attached tothe receivers by means of clamping rings 23a, 24a, and 25a, held on themby bolts.

The opening of each flange has a smaller diameter than the opening ofthe rigid receiver which carries it and which is determined, once forall, when building the machine.

It is thus possible to cut down, at will, by the use of suitableflanges, the circulation of air caused by the outer wall of the rotor,which circulation may carry along a portion of the liquids out of theirown receivers. The circulation of the vapours evolved by the liquidstreated may also be cut down to a minimum by means of said flanges.

The rigid portions of the receivers and the flanges constitute baflleswhich, as just set forth, brake the circulation of air or of vapours andwhich may be combined with one another or placed in any location deemedsuitable for adjusting said circulation.

The operation of the machine is as follows:

The machine may operate as a separator or as a clarifier. When used as aseparator, the elements of the machine appear as shown schematically inFig. 4.

The mixture of solids and liquids to be separated is introducedcontinuously in the direction of the arrow F into a container 26provided, at its base, with a spout 27 extending down into thedistributor 4, this in a known manner.

The mixture of the liquids rises, according to the theory of operationof such machines, through the holes a, 7a and the notches 6b, and theliquids are then evacuated, according to their specific gravity, towardsthe inside or towards the outside of the stack of discs 6.

The light liquid issues, in the directions of the arrows f, through theholes a of the flange 10 and the holes 16 of the bowl cap and, risinginside the collar 19, is evacuated through the space 28 between thereceivers 24 and 25.

The heavy liquid comes out along the arrows f and rises up to the spouts14, through which it passes to reach the adjustment diaphragm 18 and tobe evacuated through the space 29 between the receivers 23 and 24.

The solid, heavy impurities slide outwards, penetrating or not betweenthe discs 6 according to their size and they are partly evacuatedtogether with the heavy liquid and partly applied on the inner Wall ofthe bowl 1 and of the bowl cap 11.

The outlet device provided for the heavy liquid makes it possible, by aproper choice of the lengths and diameters of the spouts, to ensure theevacuation of a large portion of the solid impurities, denser than theheavy liquid, by acting on the evacuation speeds of the solids and ofthe heavy liquid.

The light, solid impurities, always fine, slide inwards of the stack ofdiscs 6 and are housed in the silt chamber 15 formed between said stackand the distributor 4, this under the condition that these impurities belighter than the light liquid.

The chamber 15 may be provided with an air-evacuating device which hasnot been shown.

. In principle, the surface of separation of the liquids through thestack of discs 6 may be limited by the chaindotted circumference lineshown in Fig. 2. For one direction of rotation R, the light liquid movessubstantially along the path f, while the heavy liquid moves along thetrajectory f.

The elimination of the solid materials having a diameter larger than thespacing of the discs is ensured by the shape of the notches 6b towardsthe outside of the discs.

When the machine is used as a clarifier, there is an advantage incausing the liquid to circulate as far as possible from the axis ofrotation and even outside the stack of discs. The eddy currentscreatedoutside the stack are of no importance, since the single liquid has togo through the stack of discs, by following the path covered by thelight liquid in the machine used as a separator.

To this eifect, the orifices 7a of the lower flange 7 are stopped byplugs 30 (Fig. 5), and the spouts 14 of the bowl cap are stopped byplugs 31.

The liquid to be clarified is introduced along the arrow F and, passingthrough the radial channels 5 of the distributor '4, it passes throughthe stacks of discs 6 following the direction of the arrows f, and isevacuated through the space 28 between the receivers 24 and 25.

It should be noted that, in some cases, the orifices 7a should bestopped even when the machine is to operate as a separator.

' What I claim is: V

1. In a centrifugal machine for separating and clarifying liquids, arotor consisting of a bowl; a vertical shaft located on the axis of saidbowl for driving it in a high speed rotating motion; a distributorbringing the liquid to be treated to the center of said bowl; a statorcomprising a container divided into several chambers for receiving thevarious divided portions of the liquid treated; a separator unit locatedinside said bowl and comprising a plurality of plane thin dividing discsarranged perpendicularly and concentrically with respect to the axis ofthe shaft driving the bowl, said dividing discs being spaced from eachother by spacing washers that are located outside of the outward spiralpath of the heavier liquids and solids and outside of the inward spiralpath of the lighter liquids and solids; a plurality of orifices formedin said plane dividing discs, said orifices being adapted to be leftfree or stopped according to whether it is desired to allow the liquidto be treated to reach the axis of the bowl or to send it back towardsthe outside of the discs; a plurality of assembly holes formed in saidplane dividing discs; support rods passing alternately through saidassembly holes in the dividing discs and the spacing washers, thusforming a stack of said discs; and two flanges located respectively atthe ends of said stack and in which the ends of said support rods arefixed so as to form with said dividing discs and said spacing washers, aremovable block, said block being itself built in a dynamically balancedstate.

2. In a centrifugal machine for separating and clarifying liquids, arotor consisting of a bowl; a vertical shaft located on the axis of saidbowl for driving it in a high speed rotating motion; a distributorbringing the liquid to be treated to the center of said bowl; a statorcomprising -a container divided into several chambers for receiving thevarious divided portions of the liquid treated; a separator unit locatedinside said bowl and comprising a plurality of plane thin dividing discsarranged perpendicularly and concentrically with respect to the axis ofthe shaft driving the bowl, said dividing discs being spaced from eachother by spacing washers that are located outside of the outward spiralpath of the heavier liquids and solids and outside of the inward spiralpath of the lighter liquids and solids, said spacing washers having assmall a diameter as possible and a thickness which depends upon the sizeand nature of the particles in suspension in the liquids to be treatedin the machine; a plurality of orifices formed in said plane dividingdiscs, said orifices being adapted to be left free or stopped accordingto Whether it is desired to allow the liquid to be treated to reach theaxis of the bowl or to send it back towards the outside of the discs; aplurality of assembly holes formed in said plane dividing discs; supportrods passing alternately through said assembly holes in the dividingdiscs and the spacing washers, thus forming a stack of said discs; andtwo flanges located respectively at the ends of said stack and in whichthe ends of said support rods are fixed so as to form with said dividingdiscs and said spacing washers, a removable block, said block beingitself built in a dynamically balanced state and being adapted toaccommodate spacing washers the thickness of which varies from one blockto another in a group of said blocks, each block in said group of blocksthus being capable of being assigned to a predetermined type of liquidto be treated in the machine.

3. A centrifugal machine according to claim 2, in which the planedividing discs have a central opening through which the distributor ofthe machine passes for forming around said distributor a silt chamberfor the light liquid, the upper flange of the stack of dividing discsbeing provided with apertures located above said chamber for allowingthe evacuation of said light liquid.

4. A centrifugal machine according to claim 2, in which the planedividing discs have a central opening through which the distributor ofthe machine passes for forming a silt chamber; the upper flange of thestack of dividing discs being provided with apertures located above saidchamber for allowing the evacuation of the light liquid flowing throughsaid silt chamber; the orifices formed in the plane dividing discscomprising radial slots located on the peripheries of said discs and thelower flange of the stack of dividing discs being provided with openingslocated opposite said slots in the dividing discs so that the inlet ofliquid is effected inside said stack with no risk of clogging betweenthe discs.

5. A centrifugal machine according to claim 2, in which the planedividing discs have a central opening through which the distributor ofthe machine passes for forming a silt chamber; the upper flange of thestack of dividing discs being provided with apertures for allowing theevacuation of the light liquid flowing through said silt chamber; theorifices formed in the plane dividing discs comprising radial slotslocated on the peripheries of said discs and the lower flange of thestack of dividing discs being provided with openings located oppositesaid slots in the dividing discs so that the inlet of liquid is effectedinside said stack with no risk of clogging between the discs, said lowerflange openings being adapted to be closed by plugs thereby compellingthe liquid to pass outside the stack.

6. in a centrifugal machine for separating and clarifying liquids, afixed stator member provided at its upper central portion with adownwardly extending conduit for introducing said liquids; a rotormember adapted to be rotatably driven at high speed and including asubstan tially cylindrical bowl and a cover member detachably andhermetically fixed on the upper part of said bowl; a driving shaftcentrally mounted on the lower part of said bowl; a distributor mountedcentrally of said rotor member and in communication with said liquidconduit; a plurality of radially disposed channels formed between thelower face of said distributor and the base of said bowl; a cylindricalself-cleaning separator unit comprising a stack of flat discs of equaldiameters, said discs being spaced apart and mounted on and around saiddistributor; a plurality of orifices formed in said discs in verticalregister to form vertical passages through said stack, each of saidpassages being adapted to communicate with the outer extremity of one ofsaid radially disposed channels; an outer annular chamber formed betweenthe inner walls of said bowl and the outer side of said stack to providea passage for heavier liquids and to form a deposit chamber for heaviersolid matter; an inner silt chamber formed between said distributor andthe inner side of said stack to provide a passage for lighter liquidfractions and to form a deposit chamber for lighter solid matter; andseparate channel means communicating respectively with said outer andinner chambers and leading into parts of said stator member for takingofl. the separated liquids.

7. In a centrifugal machine as claimed in claim 6 and which isespecially adapted for the clarification of liquids, the lower orificesof said vertical passages in the separator unit being closed by plugsand the channel means leading from said outer chamber also being closed,so that the entire liquid flow from said bowl takes place inwardlythrough said discs and then upwardly into said channel means leadingfrom said inner chamber.

8. In a centrifugal machine for separating liquids, a fixed statormember provided at its upper central portion with a downwardly extendingconduit for introducing said liquids; a rotor member adapted to berotatably driven at high speed and including a substantially cylindricalbowl and a cover member detachably and hermetically fixed on the upperpart of said bowl; a driving shaft centrally mounted on the lower partof said bowl; a distributor mounted centrally of said rotor member andin communication with said liquid conduit; a plurality of radiallydisposed channels formed between the lower face of said distributor andthe base of said bowl; a cylindrical self-cleaning separator unit formedby a plurality of flat thin discs arranged at right angles to andconcentrically with the axis of said bowl, said discs forming separatorplates and being provided with vertically aligned assembly holes;support rods extending through the aligned assembly holes of said discs;a flange forming the lower extremity of said distributor, said rodsbeing fixed at their lower extremities to said flange and said platesbeing spaced apart by spacing washers threaded on said rods, the stackassembly thus formed being clamped together by nuts screwed on the upperextremities of said rods; a plurality of orifices formed in said discsin vertical register to form vertical passages through said stackassembly, each of said passages being adapted to communicate with theouter extremity of one of said radially disposed channels; an outerannular chamber formed between the inner walls of said bowl and theouter side of said stack assembly to provide a passage for heavierliquids and to form a deposit chamber for heavier solid matter; an innersilt chamber formed between said distributor and the inner side of saidstack assembly to provide a passage for lighter liquid fractions and toform a deposit chamber for lighter solid matter; and separate channelmeans communicating respectively with said outer and inner chambers andleading into parts of said stator member for taking off the separatedliquids.

9. In a centrifugal machine as claimedin claim 8, in which saidcylindrical separator unit itself is in a dynamically balanced state.

10. In a centrifugal machine as claimed in claim 8, in

which the orifices formed in said discs comprise radially thatthey-liesubstantially out ofthe outward spiral path disposed slotsspaced apart uniformly on the periphery of theheavier liquids and solidsand also out of the inof said discs and extend inwardly at least to thecritical wardspiral path of the lighter liquidsand solids. diameter ofthe surface of separation of the liquids treated in the machine, saidslots communicating with openings 5 i a 7 References Cited inthe file ofthis Patent formed in said flange so as to permit communication of t VUNITED STATES PATENTS said vertical passages with the outer extremitiesof said 2,403,089 L'ars n, 2, 1946 radially disposed channels.

11. In a centrifugal machine as claimed in claim 8, FOREIGN PATENTS inwhich said support rods and spacing washers are s0 10 1 8,816 SwedenJan. 17, 1905 disposed in relation to said vertical passages for theliquid, 15,480 Great Britain 1911

